According to the Grant County Sheriff's and Grant County PUD officials, a malfunction with electrical equipment led to an early Friday morning explosion that injured six workers, two of them seriously.

Harborview Medical Center in Seattle confirmed five of the six were sent to their facility, suffering from burns of varying degrees. Two men are in critical condition, two workers in their 40's, and a 58-year-old worker was listed as satisfactory. The condition of the other workers was not known.

The explosion occurred around 7:15am, but did not affect the safety or structural integrity of the dam in any way. The dam, built in the 1950's has ten turbines and ten generators to produce electricity for the Grant County PUD.

The investigation into what caused the explosion continues.